Central nervous system

The brain is known to be the maestro of the body, which initiates different movements”. This complex two-lobed organ controls everything in our bodies. It controls thoughts, emotions, touch, memory, motor skills, hunger, breathing, temperature, vision, and every process any human body can possibly do. But the brain doesn’t work alone. Together with the spinal cord, they make up the central nervous system. 

The brain sends and receives electrical and chemical signals throughout the body. Different signals mean different processes and the brain can interpret them all. Some signals make you feel pain or tiredness, while others make you feel touch.   

But as we elaborated, the brain doesn’t work alone. It sends its messages through the spine and across the body’s vast network of nerves. These nerves reach the distant extremities of the body. 

What is the Spinal cord?

It is the thin tubular bundle of nervous tissue and cells that extend from the brainstem to the lumbar vertebrae. In every adult, the spine consists of 33 backbones or also known as vertebrae. Just as the skull protects the brain, the spine protects the spinal cord. 

The spinal cord controls and receives sensory input from the voluntary muscles of the trunk and limbs. It runs from the medulla oblongata to the first lumbar vertebra's lower border.

The spinal cord is one of the most complicated, but interesting, parts of the nervous system to examine. Its intricate connections, developmental abnormalities, lesions, and clinical manifestations are rather overpowering, necessitating a deeper knowledge of its anatomical and physiological origins.

A fundamental understanding of spinal cord anatomy is required for the interpretation of clinical signs and symptoms, as well as the comprehension of pathologic processes involving the spinal cord.

It consists of bundles of the axons of the nerves forming pathways that carry incoming and outgoing messages between the brain and the rest of the body. It is like the spinal cord contains internal circuits of nerves. These circuits control coordinated movements of the body such as walking and swimming. They can also control urination and different reflexes such as the knee reflex. 

The spinal cord is cylindrical in shape and greyish white in color. It arises from the cranial part as a continuation of the medulla oblongata, a part of the brain stem. Then, it extends down through the vertebral canal. And just like the brain, the spinal cord is surrounded by three layers of tissue called the meninges and contains cerebrospinal fluid. 

The spinal cord is a component of the central nervous system that is cylindrical and elongated in shape. It is one of the spinal canal's most essential contents. It appears as an extension of the medulla oblongata, the lowest portion of the brain stem.

In an adult, it starts at the first cervical vertebra and terminates at the first lumbar vertebra. However, in early children, the spinal cord is significantly longer in comparison to the length of the vertebral column. It generally finishes much lower, near the top border of the third lumbar vertebrae.

The spinal cord ends at the level of the second lumbar vertebrae, tapering off, forming a structure called the Conus Medullaris, which consists of bundles of the spinal nerves that arise from the end of the spinal cord. This way, the spinal cord only occupies two-thirds of the spinal canal. 

Like the brain, the spinal cord is composed of grey matter and white matter. The center of the spinal cord is butterfly-shaped and consists of grey matter, while the outer area of the spinal cord consists of white matter. 

The highly delicate and sensitive spinal cord, like the brain, is well-protected by a robust bony-cage created by the vertebral arch and body. They join to create a lengthy spinal column (spinal cavity) that contains the spinal cord. Millions of neurons are housed in the spinal cord, and their bundled fibers run as ascending and descending tracts.

The dura mater, arachnoid mater, and pia mater are the three meninges that entirely surround the spinal cord (from outside to inside). The presence of cerebrospinal fluid (CSF) within the subarachnoid space provides additional protection and cushioning.

As for the spinal nerves, they are 31 pairs that emerge from the cord between the vertebrae. Each nerve emerges in two short branches: 

• One is at the front of the spinal cord, which is called the motor or anterior root.
• One is at the back of the spinal cord, which is called the sensory or posterior root.

The motor roots carry commands from the brain to the skeletal muscles to control movements of the body. On the other hand, the sensory roots carry sensory information such as pain, temperature, touch or limb position to the brain from different parts of the body. 

This highly organized system works so efficiently, controlling different parts of the body in a very accurate way. But sometimes things don’t work as planned in cases of injuries or diseases. 

What are Spinal tumors? 

Spinal cord tumors (SCTs) are a varied category of rare neoplasms that arise from tissues in and around the spinal canal. They frequently have a slow beginning and progression of signs and symptoms, which might include back pain, extremities weakness, sensory changes, and bowel or bladder incontinence. Meningiomas and neurofibromas are the most frequent SCTs seen in the extramedullary space.

Intramedullary SCTs, such as ependymomas and astrocytomas, are less common. The most beneficial screening test for SCT diagnosis is enhanced magnetic resonance imaging; myelography and computed tomography might also be useful. The majority of SCTs are surgically treatable and can be partially or completely removed.

Spinal tumors can arise from: 

• Spinal canal. 
• Spinal bones and it is then called a vertebral tumor. 
• The spinal cord itself. 
• The coverings of the spinal cord.

These abnormal cells grow uncontrollably and non-stop until they form a mass within the spinal canal. And just like any tumor, spinal tumors can be benign or malignant. 

They can also be classified into primary or secondary tumors:

• Primary tumors are the ones that originate from the spine or the spinal cord itself. 
• While secondary tumors are the tumors that arise elsewhere in the body and spread to the spine and spinal cord, it is also called metastatic tumors. 

When doctors describe spinal tumors, they usually refer to them in two ways: 

• By the region of the spine in which the tumor started. And the spine is divided into these basic areas: cervical, thoracic, lumbar, and sacrum.
• By their location within the spine.

Primary spinal cord tumor

Primary spinal cord cancers develop from several components of the central nervous system (CNS), such as neurons, supportive glial cells, and meninges. Anatomically, spinal cord neoplasms are categorized according to the compartment of origin, either intramedullary (within the cord) or extramedullary (outside the cord) (outside the cord).

Astrocytomas and ependymomas are the most common primary intramedullary spinal cord tumors. Intradural extramedullary tumors that impact the paravertebral region, such as schwannomas, neurofibromas, and meningiomas, can spread and compress the cord by expansion. An expanding malignant lymph node may occasionally squeeze the chord.

Epidemiology of spinal tumors

The spinal cord accounts for approximately 15% of all primary CNS lesions, with an estimated incidence rate of 0.5-2.5 occurrences per 100,000 population.

The majority of initial spinal cord tumors do not spread significantly across the CNS or body. The degree of cord damage and anatomic level of cord injury influence subsequent disability.

The level of spinal cord impairment caused by a tumor varies greatly. Pain or mild sensory or motor disturbances may be the only symptoms at first. Neurologic problems become increasingly apparent as the compression proceeds, leading to impairment.

In individuals with epidural cord compression, the degree of impairment at the start of therapy is the greatest predictor of eventual disability. The objective is to detect and treat cord compression as soon as possible.

• Sex and age-related demographics

Primary spinal cord tumors have a modest male preponderance. Symptomatic hemangiomas are most common in adolescent girls and usually affect the thoracic spine.

Primary spinal cord tumors are more common in persons aged 30 to 50. People over the age of 50 are more prone to suffer from back discomfort caused by a metastatic tumor. Certain CNS tumors, such as neuroblastoma, virtually always affect children.

Clinical symptoms caused by intramedullary tumors differ depending on the individual's age. Gait abnormalities are common in children, with discomfort being mentioned very occasionally. In younger individuals, spinal cord neoplasms may show as scoliosis or torticollis.

The most common early complaint of adult patients with spinal cord neoplasms is pain, which is followed by the gradual progression of spinal cord dysfunction.

Location of Spinal tumor

The location of the tumor within the spine can be subdivided into: 

• Intradural-extramedullary:

In this location, the tumor lies inside the thin covering of the spinal cord, known as the dura, but outside the spinal cord itself. Tumors that occur in this location makes up to 40% of the spinal tumors. The most common types of tumors that occur in this location are the ones that develop in the spinal cord’s arachnoid membrane (known as meningiomas), in the nerve roots that extend from the spinal cord (known as schwannoma and neurofibromas), or at the base of the spinal cord (known as filum terminale ependymomas). Although meningiomas are benign, they are difficult to excise, and they usually recur. Nerve root tumors are also benign, however, neurofibromas can turn malignant over time. Ependymomas, on the other hand, are often large which makes it quite difficult to remove them regarding the delicate nature of the neural structure in that area. 

• Intramedullary:

 This term refers to the tumors that grow inside the spinal cord. They typically arise from two types of cells called the glial and ependymal cells. These cells make up the spinal cord. The frequency of occurrence of tumors in this location is 5%. The two most common types in this location are astrocytomas and ependymomas. Astrocytomas are more common in the thoracic region followed by the cervical region. While ependymomas are more common in the bottom region followed by the cervical region. They are often benign; however, they can be very difficult to remove. 

• Extradural. 

Tumors of this type arise outside the dura, the outermost covering of the three coverings that enclose the spinal cord. The frequency of occurrence in this location is about 55%. Tumors in this location are usually attributed to metastatic cancers. Sometimes tumors in this location extend through the intervertebral foramina which makes them partially within and partially outside the spinal canal.  

These were all the possible types and locations of spinal tumors. 

Pathophysiology

Compression of the thecal sac, spinal cord, or cauda equina, as well as compression of the attendant vascular supply, can induce neurologic symptoms such as cord edema and ischemia.

The corticospinal and spinocerebellar pathways, as well as the posterior spinal columns, are the most susceptible to mechanical pressure. Tumors can occasionally cause cavitation inside the spinal cord.

Spinal tumor symptoms

Arising from different places, spinal tumors cause a variety of symptoms. Each tumor will elicit a different set of symptoms according to its location and the affected nerves, for sure. However, there are common symptoms that can make any doctor suspect a spinal tumor. 

Back pain is the first symptom of spinal cord neoplastic illness in around 90% of adult patients. Pain frequently occurs 2-4 months before other symptoms linked with spinal cord compression.

Pain or discomfort might be radicular, confined to the back, or a combination of the two. Radicular discomfort is caused by nerve root impingement and is aggravated by movement or straining/valsalva.

Many of these tumors will present with back or leg pain initially. Others will cause leg or arm weakness, bowel or bladder problems, or clumsiness. So, all in all, most of them will lead to neurological symptoms including: 

• Radiculopathy, which means pinching of the nerve roots. 
• Myelopathy, which means compression of the spinal cord. 
• Numbness and tingling.
• Difficulty walking.
• Paralysis.

Symptom development may be fast if symptoms other than pain begin. Sensory or motor symptoms that may be attributed to the cord include limb paresthesias and focal weakness, which can show as difficulty ambulating or foot drop.

In individuals with a history of malignancy, the onset of leg weakness, paresthesias, or bowel or bladder problems should prompt early worry for cord or cauda compression. Paraplegia and bowel or bladder problems are generally discovered later. Urinary retention is the most frequent bowel or bladder problem, however either urine or stool retention or incontinence can occur.

Physical findings

Physical examination findings correspond to the location of the tumor as well as the degree and duration of cord impingement. and may contain the following:

• Local tenderness
• Motor weakness
• Sensory loss
• Reflex changes
• Ataxia
• Cauda equina syndrome 

• Tenderness

The presence of severe spinal pain and soreness is generally the initial sign of neoplastic spinal cord illness. Percussion discomfort may be felt over the afflicted spinal area. Pain that develops down the asymptomatic limb when straight-leg raising may indicate cord compression.

Coughing, sneezing, or straining may aggravate radicular back pain caused by cord compression, although this occurs with other types of mechanical back pain as well.

• Motor weakness

Motor weakness develops late in the illness phase, with thoracic or lumbar lesions producing lower extremity weakness, particularly of the flexors, and cervical lesions causing both lower extremities and upper extremity weakness, particularly of the extensors.

Almost half of patients with neoplastic spinal cord compression had some paresis, with up to 15% being paraplegic at the time of diagnosis. Lax anal sphincter tone is a late sign of spinal cord dysfunction.

• Sensory loss

On examination, a loss of feeling below a spinal level may be evident, generally beginning five dermatomes below the level of the problematic lesion. In contrast to lesions of the cauda equina, lesions above the conus generally spare the sacral dermatomes/saddle region.

• Reflexes 

Hyperreflexia below the level of the injury may result from spinal cord compression. Before the onset of hyperreflexia, there may be a phase of hyporeflexia early in the course. Spasticity or hyperreflexia may occur early, or deep-tendon reflexes may be initially hypoactive or absent. 

• Ataxia

Ataxia or a gait abnormality may result from the concurrent development of lower extremity weakness and sensory loss. Rarely, spinal cord neoplasms can cause isolated ataxia that is not caused by sensory or motor impairments.

Spinal tumor metastasis

About 85 percent of neoplastic spinal cord compression cases are caused by metastatic lesions, with the remaining 15 percent caused by original neoplastic lesions of the spine. The clinical appearance of metastatic lesions in compression is often indistinguishable from that of original illness.

The cell origin of the tumor, however, is less of a concern for the emergency physician than the resulting symptoms of spinal cord dysfunction. These individuals require prompt identification and treatment to avoid long-term consequences.

Metastatic spinal cord compression is caused by an invasive lesion in the epidural space, between the vertebral bones and the dura of the thecal sac, compressing the thecal sac, spinal cord, or cauda equina.

Systemic cancers with a tendency for spinal metastasis include the following:

• Breast cancer
• Prostate cancer
• Renal cancer
• Lung cancer
• Lymphoma 
• Sarcoma 
• Multiple myeloma

Metastatic spinal cord compression often occurs after arterial hematogenous spread of malignant cells to the vertebral bodies, followed by enlargement into the epidural space. Tumor extension through the intervertebral foramina (as is typical with lymphoma) or hematogenous dissemination to the vertebral bodies via the Batson venous plexus can also cause spread into the epidural region (particularly with prostate cancer).

The thoracic spine is the most commonly implicated location in metastatic seeding (70% of cases), with the lumbar spine coming in second (20 %). In roughly 10% of cases, the cervical spine is damaged. Around 30% of individuals have several spinal levels impacted. The lumbosacral spine is commonly affected by gastrointestinal and pelvic cancers. Lung and breast cancers have a higher risk of affecting the thoracic spine.

Intramedullary metastases (metastases to the substance of the cord) are uncommon. In such situations, the signs and symptoms are similar to those of epidural compression; however, if motor weakness is present, it is more likely to be unilateral. The treatment principles for intramedullary cancer are identical to those for epidural spinal cord compression.

Vertebral Tumors

Vertebral tumors are the types of spinal tumors that affect the bony spinal column. You may think these tumors can’t reach the spinal cord, so they don’t cause neurological symptoms. 

These tumors affect neurological functions by pushing on the spinal cord and the nearby nerve roots. As they grow within the bone, they cause severe pain, instability, and spinal fractures. Besides, if the tumor is large enough to shift the column alignment, it will cause scoliosis or kyphosis. 

Vertebral tumors can arise from the spine primarily, however, the spinal column is the most common site for bone metastasis. Research showed that around 30% and up to 70% of cancer patients will experience the spread of cancer to their spine. Common cancers that send metastasis to the spine are lung, breast and prostate. 

Lung cancer is the most common cancer to metastasize in men, and breast cancer is the most common in women. Other cancers that spread to the spine are multiple myeloma, lymphoma, melanoma, thyroid cancers, gastrointestinal tract cancers, kidney cancer and sarcoma. 

The most common primary vertebral tumor is vertebral hemangiomas. They are benign tumors that rarely cause symptoms. 

Diagnose of spinal and vertebral tumors 

Besides good history taking and thorough physical examination, some investigations are needed to confirm the presence of a spinal tumor. 

CT scans or MRIs are often needed in the initial evaluation of vertebral and spinal cord tumors. The nature of these tumors and their location necessitates such techniques to discover them. 

Treatment for Spinal tumor

If you are diagnosed with spine cancer, your doctor will advise you on the best treatment choices. This is determined by a number of factors, including the type and location of the tumor, as well as your overall health.

To treat the tumor or improve symptoms, one or more of the following treatments may be advised.

• Corticosteroids: If a spinal tumor presses against the spinal cord, certain medications (such as dexamethasone) may be used to decrease swelling. These tumors are treated as soon as possible, and are frequently treated surgically.
• Surgery: Some spinal tumors can be surgically removed. If the whole tumor cannot be removed, radiation treatment may be administered following surgery to alleviate spinal cord pressure.
• Radiation therapy: To alleviate pressure on the spinal cord, it may be administered alone or after surgery. Stereotactic radiosurgery is a cutting-edge therapy that accurately targets the spinal tumor while minimizing the damage on healthy tissue.
• Chemotherapy: These drugs may be taken orally or by injection. They may be given alone or with other treatments.

To ensure that you get a comprehensive picture and understand everything related to Spinal tumors, we invited Dr. Sang Don Kim who is a leading doctor at Bucheon St. Mary’s Hospital, Korea to address any questions you may have from an experienced medical point of view.

Interview

1. What is exactly spinal tumors and what are their classification?

Put in a simple way, there are two types of tumors that can occur in the spine. The tumors can be intradural or extradural – inside the begin in the cells within the spinal cord itself or grow in the membrane surrounding the spinal cord or the nerve roots that reach out from the spinal cord. Within the intradural tumors there are those located inside the cover of the spinal cord (the dura), but outside the actual spinal cord and those tumors that grow inside the spinal cord. Even within that division there are many types of illnesses but it is too specific, so it is hard to explain all today. Today, we should talk about a metastatic tumor that affects the spinal musculoskeletal area, which can be divided into two types. Those that grow within the musculoskeletal area and the metastatic type that enter into the area from another organ through the veins via blood. 

2. What is the etiology behind spinal tumor?

Most tumors do not have a cause. We have not yet found the causes. Most do not know the root causes. You can think of a normal cell turning into an abnormal cell. Of course, if the tumor was metastatic, we may know where it came from since it came from somewhere. So, you can think of that as the reason.

3. Which oncological disease most often cause metastasis of the spine?

For men, it is typically lung cancer. For women, it is breast cancer. Also, for men, it can be prostate cancer, blood cancer, kidney cancer, and in Korea, liver cancer. You can say that from all organs it can metastasize.

4. How can of spinal tumor be diagnosed?

First, we look for clinical symptoms. Most common would pain in the affected area of the spine. When the nerves are attacked, there can be radiant pain. When the motion nerves are attacked, there can be paralysis. In some extreme cases, the ability to urinate or excrete can be impaired. In terms of exams, visual exams are most useful. We often use X-ray, CT scan, angiography, Gol scan, and PET/CT scan. While there are many diagnosis tools, the best is an MRI with a contrast agent. 

5. What kind of treatments are out there for benign spinal tumor?

For benign spinal tumors, there is no need for treatment. There are no special symptoms, either. They are often discovered by chance. Where there is pain nor other symptoms, simply do regular checkups to see if the size is growing or if symptoms are developing. Most do not require any treatment. If treatment is needed, is there is pain, there are many ways to mitigate it. If the spine is unstable, we can do surgery and mechanically reinforce the spine. 

6. What is the treatment for more serious cases of spinal tumor?

For metastatic tumors we need surgery. Also, for local tumors, the best method is surgery. The basics of surgery is first, to avoid pain, then to use stabilize the correct position the spinal cord.

7. What is the minimally invasive surgery?

Minimally invasive surgery is used to treat degenerative spinal cords. Simply explained, we make the smallest incision possible in order to limit the damage to the area, which helps also with fast recovery post-surgery. In reality, this technique is not ideal for spinal tumor surgeries. However, if the patient is too old and the body condition is not the best, it is difficult to perform a major surgery. In such cases, we can use minimally invasive surgery techniques in order to achieve the desired results.

8. What are the devices used for minimally invasive surgery?

We use many tools and devices. For the basics, we use magnification devices, endoscopes, navigation equipment to be able to see inside, and vertebral augmentation tools.

9. What it is the advantage of minimally invasive surgery over classic or traditional ways of surgery?

Surgeries done long ago were large surgeries. The incisions were large and very open. And many ended up with inflammation and infections after surgeries. Recovery is faster so results in higher quality of life for the patients. 

10. What are the contraindications for this kind of surgery?

Just because it is minimally invasive surgery, does not mean that everything is better. When treating tumors, it is best if we remove all the tumors. But if the minimally invasive technique hinders that goal, then it does not server the patient’s goal too well. So, if the patient is young and in good health, it is better to completely take out the tumors by doing open surgery freely.

Conclusion 

Spinal cord tumors are rare neoplasms that can cause severe neurologic morbidity and death if left untreated. Primary spinal cord tumors account for 2-4 percent of all CNS neoplasms.

Primary spinal cord tumors are classified anatomically into two types: intradural intramedullary and intradural extramedullary. Gliomas are the most common kind of intramedullary tumor (infiltrative astrocytomas and ependymomas).

Early diagnosis is critical in the therapy of lesions and influences the patient's prognosis and final outcome. In instances of intramedullary disease, plain X-rays of the spine and CT scans have limited diagnostic utility. When an intrinsic spinal cord lesion is clinically suspected, magnetic resonance imaging should be conducted as soon as possible and as the initial method.

Early detection of primary spinal cord tumor signs and symptoms allows for early treatment, perhaps reducing neurologic morbidity and improving prognosis. Surgery is the primary therapy for almost all spinal cord tumors, and predictors of success include preoperative functional status, histological grade of tumor, and surgical resection extent.